Robust transducer for viscoelastic measurement

Abstract

A transducer for use in a viscoelastic analyzer of the type in which a mechanical probe member is immersed in a fluid or gel and driven to impart a desired oscillating motion to such fluid or gel whose viscoelastic properties are to be determined including means for restricting motion of the probe member of the transducer in all directions except the direction of desired oscillation motion.

What is claimed is:  
     
       1. A transducer for use in a viscoelastic analyzer of the type in which a mechanical probe member is immersed in a fluid or gel whose viscoelastic characteristics are to be determined, the probe member being driven to impart a desired oscillating motion thereto, the improvement comprising means for restricting motion of the probe member, during both periods of operation and inoperation of the viscoelastic analyzer, in the direction of the desired oscillating motion, to a region that protects the probe member from excessive displacement, and for also restricting motion of the probe member, during both periods of operation and inoperation of the viscoelastic analyzer, in any direction except the direction of the desired oscillating motion. 
     
     
       2. A transducer as in claim  1  wherein said means for restricting motion further comprises mechanical stop means for limiting deflection of tie probe member in the direction of the desired oscillating motion. 
     
     
       3. A transducer as in claim  1  wherein the probe member comprises a disposable component and a non-disposable component. 
     
     
       4. A transducer as in claim  1  wherein the means for restricting motion comprises a circular planar spring assembly coupled to the probe member for restricting motion of the probe member in all directions except along the axis of the probe member. 
     
     
       5. A transducer as in claim  4 , wherein the circular planar spring assembly comprises a pair of circular planar springs spaced apart from each other and coaxially coupled at their peripheral edges to a circular ring. 
     
     
       6. A transducer as in claim  5  wherein each of the circular planar springs compises a beryllium copper circular planar ring. 
     
     
       7. A transducer for use in a viscoelastic analyzer of the type in which a mechanical probe member is immersed in a fluid or gel whose viscoelastic characteristics are to be determined, the probe member being driven to impart a desired oscillating motion thereto, the improvement comprising stop means for limiting deflection of the probe member, both during periods of operation and inoperation of the viscoelastic analyzer, in the direction of the desired oscillating motion. 
     
     
       8. A transducer as in claim  7  wherein the probe member comprises a disposable component and a non-disposable component. 
     
     
       9. A transducer as in claim  7  wherein the stop means comprises a combination of a cover member and a magnet. 
     
     
       10. A transducer as in claim  2  wherein the stop means comprises a combination of a cover member and a magnet.